This invention relates generally to apparatus for use in conjunction with aquariums and the like, and, more particularly, to a new and improved device for filtering and aerating the water contained in an aquarium tank and for constantly maintaining the water in the aquarium tank at a predetermined level.
In order to sustain aquarium marine and plant life in an optimum environment, it is essential that the water in the aquarium tank be periodically cleaned, aerated and degassed to replenish the oxygen content of the tank water. However, equally important to such achievement of an optimum environment for the marine and plant life is the maintenance of an unchanging, constant, predetermined level of water in the aquarium tank.
The problem of obtaining an optimum environment for aquarium marine and plant life has been attacked by many as evidenced by the multitude of different filtration and aeration devices proposed in the prior art for clarifying or purifying the aquarium tank water. Some forms of filter units and/or aerator means have been simple in construction while others are rather complex in nature and, thus, costly to manufacture and maintain in good working order. In fact, the utilization of certain filtration and aeration systems oftentimes requires the use of a specially-designed and constructed, and, thus, costly aquarium tank.
Generally, conventional filtration and aeration systems usually involve the continuous flow of water from the aquarium tank into filtration means and from the filtration means back into the tank. Oftentimes, the aeration means are provided in series with the filtration means or sometimes such aeration means are separate and apart from the filtration means. Furthermore, in order to conserve space within the aquarium tank and to facilitate periodic cleaning of the filter media, in many prior art arrangements or installations the filter unit is mounted on the exterior side of one of the aquarium tank walls. Means are provided for transferring water from the aquarium tank to the exteriorly-mounted filter unit and such tank water transferring means often takes the form of a conventional siphon tube. In the usual installation, the intake end of the siphon tube within the aquarium tank is disposed at or adjacent the bottom of the aquarium tank where any sediment and foreign debris tend to settle. The following United States patents disclose filtration systems wherein a filter unit is mounted on an exterior wall surface of an aquarium tank and the filter unit is supplied with water mainly from the bottom of the aquarium tank or from the mid section thereof:
U.S. Pat. No. 2,737,490, Lambertson PA1 U.S. Pat. No. 3,135,238, Eyl PA1 U.S. Pat. No. 3,321,082, Willinger PA1 U.S. Pat. No. 3,273,717, Canterbury PA1 U.S. Pat. No. 3,835,813, Katz PA1 U.S. Pat. No. 3,693,798, White PA1 U.S. Pat. No. 3,994,807, Macklem PA1 U.S. Pat. No. 4,285,813, Stewart
While all of the filtration systems disclosed in the above-listed prior art patents are no doubt successful to some degree in removing the sediment which has settled to the bottom of the aquarium tank, such filtration systems are obviously functionally incapable of removing the proteins, amino acids, fatty acids and other proteinaceous material which accumulate and are concetrated on the top surface layer of the water contained in the aquarium tank. If such proteinaceous materials are not removed and are allowed to accumulate and become concentrated on the top surface of the aquarium tank water, the proper exchange of gases between the aquarium tank water and the ambient air is prevented to thus adversely affect the balanced interplay of certain biological and biochemical systems necessary for achieving optimum environment for the aquarium marine and plant life. Moreover, the accumulated foreign material may actually form a foul and unsightly scum on the top surface of the aquarium tank water is not periodically removed.
Numerous attempts have been made in the past to resolve the problem of skimming the top surface of the water within the aquarium tank in order to remove foreign matter therefrom. Such attempts are exemplified in U.S. Pat. Nos. 3,785,493 to Harding and 4,333,829 to Walther. While the devices and apparatuses disclosed in these patents no doubt will achieve limited success in the removal of foreign matter from the surface of the body of water contained in the aquarium tank, such patented devices and apparatuses, however, possess certain inherent functional shortcomings which diminish their effectiveness for achieving an optimum environment for aquarium marine and plant life when utilized in an aquarium water filtering and circulating system.
As pointed out hereinbefore, the achievement of optimum environment for aquarium marine and plant life depends on many factors including the important fact that the volume of the body of water in the aquarium tank must be kept as constant as possible and such volume of water should be equal to the full capacity of the aquarium tank. Moreover, by maintaining the water level constant, the unsightly deposition of salt and calcium on the inside wall surface area of the aquarium tank is eliminated. The devices and apparatuses disclosed in the two last mentioned patents are incapable of operating to maintain the level of the water in their respective aquariums constant and unchanging and the volume of the water at or close to the full water capacity of the aquarium tank.
The vast majority of aquarium water purifying systems employ an electrically-driven water or air pump for assisting in the transfer of water from the aquarium tank into the filtering means and then from the filtering means back to the aquarium tank. In those installations employing a filter unit mounted on the exterior wall surface of the aquarium tank so that the water in the filter is at the same level as in the tank, siphon tube means are generally used to draw water from the aquarium tank and discharge the same into the filter unit. The electrically-driven pump means is effective thereafter to return the filtered water back to the aquarium tank. As the filtered water is drawn from the filter unit, it is being replaced by unfiltered water from the aquarium tank through the siphoning action of the siphoning tube means. Thus, the siphon tube means serves as an important and vital link in the overall operation of the water purifying and circulating system. If for any reason the siphoning action is lost, the entire water purifying and circulating system will become inoperative. As an example, in the event of a power failure causing the pump to cease operating, the water level in the aquarium tank could be lowered by evaporation or for other reasons to a level where the intake end of the siphon tube means is exposed to the atmosphere. Similarly, the discharge end of the siphon tube means could be exposed by gravitational draining of water from the filter unit causing abnormal lowering of the water level in the filter unit below the level of the siphon tube means. Thus, in order to place the aquarium water purifying and circulating system in operation again after power is restored, it will be necessary to manually restart the siphoning action of the siphon tube means.